21534854400 has 648 divisors, whose sum is σ = 81509928864. Its totient is φ = 5623603200.

The previous prime is 21534854389. The next prime is 21534854417. The reversal of 21534854400 is 445843512.

It is a happy number.

21534854400 is a `hidden beast` number, since 2 + 1 + 534 + 85 + 4 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (648).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 94867087 + ... + 94867313.

Almost surely, 2^21534854400 is an apocalyptic number.

21534854400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21534854400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40754964432).

21534854400 is an abundant number, since it is smaller than the sum of its proper divisors (59975074464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21534854400 is an equidigital number, since it uses as much as digits as its factorization.

21534854400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The spelling of 21534854400 in words is "twenty-one billion, five hundred thirty-four million, eight hundred fifty-four thousand, four hundred".